The original issue reported here was that the select2 component sometimes renders the drop-down top-left of the screen.
This ticket has been rescoped to just upgrade select2 to 3.5.2. This was attempted as a fix, but does not address the issue.
Screencast to demonstrate the original issue in Estatio: https://drive.google.com/file/d/0B2jd2Sl73mDBZ0lqYUhtVjVRamc/view?usp=sharing
This is reproducible in both IE11 and Chrome.